Rapid Bacteriophage Quantification by Digital Biosensing on a SlipChip Microfluidic Device

The rise of antimicrobial resistance (AMR) is a majorglobal publichealth concern, and it is urgent to develop new antimicrobial drugsand alternative therapies. There has been growing interest in theuse of phage therapy as an alternative to treat AMR, and it has shownpromising results in early studies and clinical trials. Phage quantificationis a crucial step in the development and application of phage therapy.The traditional double-layer plaque assay requires cumbersome manualoperations and typically takes up to 18 h to yield a rough phage estimation.Spectrophotometry, flow cytometry, and PCR-based methods cannot distinguishbetween infectious and noninfectious phages. Here, we developed adigital biosensing method for rapid bacteriophage quantification ona digital phage SlipChip (dp-SlipChip) microfluidic device containing2304 microdroplets in 3 nL. By compartmentalizing the phages and bacteriain nanoliter droplets and analyzing the growth profile of bacteriaat 3 h, the number of infectious phages can be precisely quantified.The results from the dp-SlipChip were consistent with the traditionaldouble-layer plaque assay method and exhibited higher consistencyand repeatability. The dp-SlipChip does not require a complex fluidichandling instrument to generate and manipulate droplets. This SlipChip-baseddigital biosensing method not only provides a promising tool for rapidphage quantification, which is important for the use of phages inclinical practice to treat antimicrobial-resistant bacteria, but canalso be used as an ultrasensitive, high-specificity method to detectbacteria. Furthermore, this approach can be applied to other digitalbiology studies that require analysis at the single-object level.

Automated summary

The rise of antimicrobial resistance is a global health concern, and there is a need for new antimicrobial drugs and alternative therapies. Phage therapy has shown promising results as an alternative treatment for antimicrobial resistance. Researchers have developed a digital biosensing method on a microfluidic device for rapid quantification of infectious bacteriophages. This method provides a promising tool for phage quantification in clinical practice and can also be used for ultrasensitive and high-specificity bacteria detection.